Catherine Zeta-Jones and Michael Douglas
The name for this cut comes from 18th-century Versailles, where courtiers wore ship-shaped rings as a sign of their rank. Today the marquise can be worn lengthwise (like the vertical ring Victoria Beckham has) or sailing sideways across the finger, as Catherine Zeta-Jones's horizontally set, 10-carat marquise does. 3.3-carat marquise-cut diamond in platinum, Fred Leighton, $65,000; 212-288-1872. Photo by James Worrell

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